The configuration that any of multiple relay devices performs port mirroring, and a frame mirrored by the port mirroring (that is, replicated) is transferred to a monitoring device of the frame through one or more other relay devices is referred to herein as remote monitoring.
Regarding the remote monitoring, a tunnel for transferring a mirror frame from a switch that has performed port mirroring to a measurement device connected to another switch is configured by distributing a label table to each switch as multiple relay devices from a management server. The mirror frame is a mirrored frame. The tunnel is considered to correspond to a transfer path of the mirror frame.